Variable pitch propeller control



1942- J. H. HAMMOND, JR, AL 2,300;419

VARIABLE PITCH PROPELLER CONTROL Filed March 25, 1940 NEY Patented Nov. 3, 1942 UNITED STATES PATENT OFFICE 2,300,419 VARIABLE PITCH PROPELLER CONTROL John Hays Hammond, Jr., Gloucester, and George A. Colley, Newton Center, Mass.; said Colley assignor to said Hammond, Jr.

Application March 25, 1940, Serial No. 325,693 2 Claims. (01. 170-1356) This invention relates to variable pitch propellers and more specifically to means for varying the pitch of a propeller so as to maintain the torque of the propeller shaft substantially constant under varying conditions of wind and weather.

The invention provides torque responsive means, operated by the propeller shaft, which directly controls means for varying the pitch of the propeller blades in such a way as to maintain the propeller shaft torque constant.

The invention also provides means for varytions of parts hereinafter set forth and claimed.-

Although the novel features which are believed to be characteristic of this invention will be more particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization, may be better 'understood by referring to the following'description, taken in connection with the accompanying drawing forminga part thereof, in which the.

single figure illustrates diagrammatically the sysmarine vessel.

In the following description and in the claims parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as will permit.-

Referring to the accompanying drawing, the hull of a marine vessel is indicated at H. vessel is shown as driven by means of a propeller I2 which is provided with adjustable blades I3. The propeller I2 is attached to the end of a hollow shaft l5 which passes through an outboard bearing IS and a thrust bearing ll. The'shaft I5 is driven by a prime mover which may be of any desired type .and is preferably provided the art with a governor, not shown, for maintaining a constant speed .of rotation.

This

king the rate of change of pitch of the propeller tern as applied to the driving mechanism of a The blades I3 are connected to a variable pitch mechanism l8 which'may be of any well known and standard construction such as that manufactured by the Escher-Wyss Company of Zurich, Switzerland, the details of which form no part of the present invention and are accordingly not specifically set forth herein. This mechanism, in general, comprises a rod [9 slidable longitudinally within the shaft I5 and connected to control the pitch of the blades I3. The rod I9 is actuated by a piston 2! ma fluid pressure cylinder 21a. Fluid foractuating the piston 21 is supplied by a pump 26 through a control valve 25 and a distribution valve 25a which communi-' cates with the cylinder 210. through ducts, not shown, in the shaft I5. A motor 2| rotates a worm 22 which operates to move the upper end of a floating lever 23, which, in' turn, is pivoted to the-end of a valve rod 24 which controls the valve 25.

The piston 21 is connected by a rod 28 to a collar 29 which is slidably mounted on the shaft I5 and engages the lower end of the lever 23 so that the position of this end of the lever corresponds to the pitch of the bladesv l3.

The upper end of the lever 23 is connected by a wire 30 to an indicator 3| which shows the pitch at which the blades I3 are set. Stops 32 are provided for limiting the maximum and minimum pitch of the blades l3. The fiuid pump 26 is driven either by a motor 33 or a belt 35 from the shaft IS. A reservoir 36 and a supply tank 31 are provided for the necessary fiuid.

It is to be understood that other pitch control devices. may be employed in place of that referred to above for varying the pitch of the propeller blades l3 in response to actuation of the motor 2|; A particular type is shown for pur poses of illustration only.

Attached to the'shaft I5 is a shaft-horsepower meter 38 which may be of the type manufactured 'bythe General Electric Company of Schenectady, New York, the details of which form no part of the present invention and are accordingly not specifically set forth herein. This mechanism, in general, comprises two'gears 39 and 40 which are attached to the shaft l5 at a suitable spacing. Mounted adjacent to the gears 39 and 40 are two U-shaped permanent magnets 4| and 42 which are provided with teeth on the faces adjacent to the gears 39 and 40. The

' coils 43 and 44 which are connected to a horsemagnets 4| and42 areprovided with armature power-hour totalizer 45 and a horsepower indicator 46 which is provided with a pointer 53 While the meter shown is the type manufactured by the General Electric Company of Schenectady, New York, it is to be understood that any other suitable type of horsepower or torque on the scale the horsepower being transmitted by the shaft l5.

meter may be employed for the present purpose.

In accordance with the present invention, means is provided for controlling the motor 2| by the position of the pointer 53. In the embodiment shown this is accomplished by providing a contact 55, attached to, but insulated from, the pointer 53 and a ring 51 surrounding the pointer 53 and rotatably mounted with respect thereto. The ring 51 carries a segment of a worm gear 58. Meshing with the gear 58 is a worm 53 which may be rotated by means ofa knurled knob 50. Mounted on but insulated from the ring 51 are a plurality of contact segments 5| to 55 which are selectively engaged by the contact 55.

The segments 5| and 55 are connected by flexible conductors to two conductors and 1| which in turn are connected to the reversing windings of the motor 2|. The segments 52 and 53 are connected by flexible conductors to two resistors and 11 which in turn are connected to the conductor 10. The segments 54 and 55 are connected by flexible conductors to two resistors 50 and 5| which are in turn connected to the conductor 1 I. The return lead from the windings of motor 2| is connected through a battery 82 to the blade of a three position witch 83. a The center contact of this switch is connected to the conconductor- 1| and the lower contact is connected to the conductor 15.

Operation In the operation of the form of the invention shown, the pitch of the blades I3 is first set at the normal operating angle for the conditions under which it is desired to operate the vessel. The setting of the propeller blades I3 is accomplished by moving the blade of the switch 83 into the upper or lower position, which will cause the motor 2| to move the upper end of the lever 23 to the left or right to increase or decrease the pitch in a well known manner, the angle of pitch being indicated by the pointer of the indicator 3|.

The shaft-horsepower meter 35 is so constructed that when there is no power transmitted by the shaft l5 and therefore no torque produced in this shaft the teeth of the two, gears 39 and 45 will be exactly opposite the corresponding teeth of the magnets 4| and 42 at the same instant. As the windings 43 and 44 are reversed the respective voltages generated therein will be exactly 180 out of phase so that no voltage will be applied to the indicator 45 and the pointer 53. will be in the zero position. As power is transmitted by the shaft l5 a torque will be produced in this shaft proportional to the horsepower transmitted, thus producing a slight twist between the gears 33 and 40 so that the teeth of these gears will not be exactly opposite the corresponding teeth of the magnets 4| and 42 at the same instant.

The voltages generated in the two windings 43 V and 44 will then not be exactly 180 out of phase so that a resultant voltage will be produced which is proportional to both the shaft twist and the propeller speed. This voltage is applied to the indicator 45 the pointer 53 of which will indicate Atfer the vessel is brought up to the desired speed the pointer 53 will indicate the horsepower required to maintain this speed under the existing conditions of wind and weather, which in this case is shown on the scale 54 as 5,000 horsepower. The ring 51 is then rotated by means of the knurled knob 55 until the insulation between the segments 53 and 54 engages the contact 55. The blade of the switch 83 is then moved into engagement with the center contact.

If the conditions under which the vessel is travelling should change adversely, such as encountering a strong head wind or running into a heavy sea, the power transmitted by the shaft l5 will increase, thus producing a greater torque .tact 55, the upper contact is connected to the 1 and causing an increased twist between the gears '39 and 40, which will shift the teeth of these gears more out of alignment and cause a greater voltage to be applied to the indicator 45. This in turn will-cause the pointer 53 to move in a counter clockwise direction to indicate an increase of torque or horsepower. The contact 55 will then engage the segment 53 and a circuit will be closed from the battery 52 through the resistor 11 to the motor 2|, causing the motor to rotate slowly in a direction to move the upper end of. the lever 23 to the right. This will move the valve 24 to the right which will allow fiuidunder pressure to pass from the pump 25 to the cylinder 21a by means of the ducts in the shaft 15. This will actuate the piston 21 which, by means of the rod l9 and the link mechanism will cause the propeller blades |3 to slowly decrease their pitch, thereby decreasing the torque until the indicated horsepower again reaches 5,000 at which time the contact 55 will again rest on the insulation between segments 53 and 54 and stop the motor 2|.

If the torque should decrease due to a followingwind or other favorable conditions, the reverse action would take place, thus causing a gradual increase in pitch of the propeller blades which would cause the torque to be increased until the contact 55 again rests on the insulation between the segments 53 and 54, at which time the motor 2| would stop.

If the changed conditions cause a rapid change of torque so that the contact 55 engages either segment 55 orsegment 52, then the resistor II or 15 will be thrown in circuit with the motor 2| instead of the resistor or 11 as already described. As resistors 8| and 15 have less resistance than resistors 50 and 11 the motor 2| will be caused to rotate faster, thus changing the propeller pitch more rapidly to take care of the more rapidly changing conditions.

If the conditions change so quickly that the contact engages either segment 5| or segment 55, then no resistance will be thrown in the circuit of the motor 2| and it will rotate at its maximum speed, thus changing the propeller pitch at a maximum rate. The stops 32 are provided so that the propeller pitch is prevented from exceeding certain limits beyond which it could not operate efliciently under any conditions.

By the system above described the pitch of the propeller blades I3 is varied to cause-the prothe propeller, but a more abrupt changein torque will be promptly and quickLv corrected by a more rapid actuation of the pitch control means. The meter 38 is set forth herein as a horsepower meter. It is to be understood, however, that with the shaft l5 operating at constant speed the meter will measure directly changes in torque or twist of the shaft itself, the horsepower being proportional to the torque or twist of the shaft under these conditions.

The invention has been shown as applied to the propulsion of vessels. It is to be understood, however, that it is capable of various uses where a constant torque is required, and that various changes and modifications may be made therein as will be readily apparent to a person skilled in the art.

Although only a few of the various forms in which this invention may be embodied have been shown herein, it is to be understood that the invention is not to be limited thereto but. is only to be restricted in accordance with the scope of the following claims.

What is claimed is:

1. In a system for driving a vessel, an engine provided with a governor malntaining'the engine ipeed substantially constant, a propeller having actuated by said last means to actuate said pitch control means so as to vary the pitch of said blades in a manner to maintain constant the horsepower being transmitted by said drive shaft and at a speed which varies in accordance with the amplitude of change of horsepower being transmitted, the speed of operation of the pitch control means being greater when the amplitude of changein horsepower is greater and vice .versa, regardless of the direction of said change.

2. In a system for driving a vessel, an engine provided with a governor maintaining the en ine speed substantially constant, a propeller having blades, means controlling the pitch of said blades, a drive shaft driving said propeller, means directly responsive to both torque and speed of said drive shaft to measure the instantaneous horsepower being transmitted thereby, said means including a plurality of contacts adapted to be selectively closed in accordance with the direction and amplitude of change in horsepower,

alades, means controlling the pitch of said blades,

a. drive shaft driving said propeller, means directly responsive to both the torque and speed if said drive shaft to measure the instantaneous :iorsepower being transmitted thereby, and means and control circuits associated with said contacts to actuate said pitch control means in a direction and at a speed corresponding to the relative position of the respective contacts so as to vary the pitch of said blades in a manner to maintain v constant the horsepower being transmitted by said drive shaft and at a speed which varies in accordance with the amplitude of change of horsepower being transmitted.

JOHN HAYS HAMMOND, JR. GEORGE A. COLLEY. 

